Highly Selective Electrocatalytic Reduction of CO₂ into Methane on Cu–Bi Nanoalloys

Abstract

Methane (CH4), the main component of natural gas, is one of the most valuable products facilitating energy storage via electricity conversion. However, the poor selectivity and high overpotential for CH4 formation with metallic Cu catalysts prevent realistic applications. Introducing a second element to tune the electronic state of Cu has been widely used as an effective method to improve catalytic performance, but achieving high selectivity and activity toward CH4 remains challenging. Here, we successfully synthesized Cu-Bi NPs, which exhibit a CH4 Faradaic efficiency (FE) of as high as 70.6% at −1.2 V vs reversible hydrogen electrode (RHE). The FE of Cu-Bi NPs has increased by approximately 25-fold compared with that of Cu NPs. DFT calculations showed that alloying Cu with Bi significantly decreases the formation energy of *COH formation, the rate-determining step, which explains the improved performance. Further analysis showed that Cu that has been partially oxidized due to electron withdrawal by Bi is the most possible active site.

Elucidating the structure-dependent selectivity of CuZn towards methane and ethanol in CO2 electroreduction using tailored Cu/ZnO precatalysts

“…The 𝛥𝐸 ! "# value found for the Cu (111) slab matches that previously reported in the literature 40. The 𝛥𝐸 !"$!"…”

“…"# , as the activity descriptor and utilized the Computational Hydrogen Electrode model to evaluate the energetics of the elementary proton transfer step (see also ESI). 39,40 We considered only Cu sites as the catalytic active ones because Cu is the only metal known to form CO2RR products beyond CO. 41,42 As illustrated in Figs. 7a and S15-S16, the 𝛥𝐸 !…”

“…"# value found for the Cu (111) slab matches that previously reported in the literature. 40 The 𝛥𝐸 !"$!" * value found for the Cu (111) slab is in good agreement with that previously reported in the literature for CO adsorption, and is overestimate with respect to the experimental value.…”

Recent Advances in Bimetallic Cu‐Based Nanocrystals for Electrocatalytic CO2 Conversion

“…Wang et al. catalyzed CO 2 RR with BiCu alloy nanocrystals [33] . The results manifested that multiple products of CO, CH 4 , C 2 H 4 , H 2 , and HCOOH could be obtained, and alloying Bi with Cu significantly elevated the selectivity in CH 4 .…”

Metal‐based Heterogeneous Electrocatalysts for Electrochemical Reduction of Carbon Dioxide to Methane: Progress and Challenges

“…CuBi . Wang and coworkers reported the synthesis of a Cu−Bi bimetallic nano‐catalyst with tunable elemental compositions, which exhibited an improved activity and selectivity for CO 2 ER into CH 4 [22] . In particular, at −1.2 V, compared with Cu NPs, the Cu 7 Bi 1 nanoparticles showed 25‐fold enhancement for selectivity for CH 4 over C 2 H 4 4‐fold enhancement for CH 4 partial current densities (Figure 4).…”